Excavator crawler mechanism

ABSTRACT

An endless track crawler mechanism has a plurality of bogie yokes that each contain a pair of rotatable bogie rollers and are pivotally mounted on two opposite sides of a chassis of said mechanism to support said chassis. At least two of said bodie yokes are affixed to said chassis by a bogie shaft56 that provides shaft limited vertical translation of said two bodie yokes.

' United Statesaten [191 Talley [4s] ay 29,1973

[54]- EXCAVATOR CRAWLER MECHANISM [75] Inventor: Robert E. Talley, Racine, Wis. I

[73] Assignee: ucyrusErie'Company', South Mil- I waukee,` Wis. I

[22] Filed: Aug.9,1971

[2l] Appl. No.; 169,963

[s2] Us. ci.` 18o/9.5, 305/27 [51] im, ci. Baza ss/14 [58] Field of Search ..180/9.2 R, 9.*2 C,

[56] References Cited UNITED STATES. PATENTS `3,419,097 12/196'8 Nqdweu ..'.v....-....18o/9.5-x

1,725,817 8/1929 Mitchell L ..305/27 1,503,616 8/1924 Wickersham l 80/9.5

FOREIGN PATENTS OR APPLICATIONS 1,101,178 3/1961 Germany 18o/9.5

Primary Examiner- Richard J. Johnson Attorney-Thomas O. Kloehn, Arthur H. Seidel and John A. Thierry [57] ABSTRACT An endless track crawler mechanism has a plurality of bogie yokes that each contain a pair of rotatable bogie rollers and are pivotally mounted on two opposite sides of a chassis of said mechanism -to support said chassis. At least two of said bodie yokes are affixed to said chassis by a bogie shaft56 that provides shaft limited verticaltranslationvof said two bodie yokes.

'5 Claims, 6 Drawing Figures PATENTEU m2 91975 3', 7 3 5 a 3 0 SHEU 1 nf d INVENTOR ROBERT E. TALLEY ATTORNEY PATENTED MAY 2 9 |975 SHEE 2 UF d INVENTOR ROBERT E. TALLEY ATTORNEY PATENTEUHAYasIQH 3,735,830

SHEET 3 0F 4 ATTORNEY PATENEnu/waels 3,735,830

, snm u of 4 ATTORNE Y BACKGROUND OF THE INVENTION The present invention was created as a new type of crawler truck for strip mining shovels, which are immense power shovels usedr to move overburden hunbe used will illustrate the situation. A revolving frame of the shovel clears the ground by 33 feet. The boom foot pin on top of the revolving frame is 40 feet above the ground, and the boom itself is 170 feet long. The dipper has a capacity of 130 cubic yards, a maximum dumping height of 117% feet, a maximum dumping radius of 163 feet, and a weight of 13,700,000 pounds. The revolving frame is rotatably mounted on a base supported by four crawler type trucks, one truck at each comer of the base, by means of an automatically leveling, hydraulic jack suspension system. Each crawler truck is composed of a welded steel frame on each sideof which is a track comprising cast links of heat treated steel, that are connected by special steel pins. The loads from the base are transmitted to the trucks through the hydraulic jacks and the trucks must be capable of supporting the entire maximum weight of shovel, load, propel and digging stresses that can be irnposed upon them.

As-strip mining shovels increased in size, a point was reached, at and beyond which the frequency vof crawler link Ybreakage suddenly increased rapidly. Where a crawler mechanism which would nd support on no less lthan two contact points in any terrain had been successful in the past, these same structures commensurately increased in size cease to perform acceptably in many terrains on newer and larger machines. It was discovered that the stresses that were being concentrated in a single track of a dual crawler when supported at two points exceeded the strength of the track.

pHence, either a vastly strengthened track was needed,

or some means was needed to ensure broader distribu-v tion of the stresses imposed on the track, and the present invention provides the latter.

. The prior art was no aid to the solution of this problem. There `are several prior systems developed to maintain multiple points of contact of -a track'with the ground but they are designed for use with a track laying vehicle such as a tank or the like, the entire body of which is supported byV several tracks as disclosed in U.S.y Pat. Nos'. 1,317,653, 1,547,043, 1,862,329., 2,223,490 and 2,374,240. Such systems are not applicable to the instant invention because of the peculiarly unique stress forces that are placed on the.tracks of trucks that act to support a large strip mining shovel, in contrast to the relatively smallerstress forces on the tracks of the vehicles disclosed in the above listed patents.

SUMMARY OF THE INVENTION The present invention relates to an endless track crawler mechanism for large strip mining shovels and more specifically, the invention resides in a plurality of bogie yokes that are pivotally mounted to the chassis of the crawler mechanism by a pair of bogie shafts, one of which provides its connected yokes with a limited freedom of movement in a generally vertical direction. The yokes each mount a pair of rotatable bogie rollers and are surrounded by a pair of endless tracks.

As a result, structures embodying the present invention manifest advantages heretofore unavailable with crawler mechanisms known to the prior art. Specifically, the salient objects and advantages of the present invention as set forth above may be summarized as follows:

To provide an endless track crawler mechanism having a highly flexible track engaging support structure which readily conforms to inequality of the terrain on which the vehicle traverses;`

To provide an endless track crawler mechanism wherein the load supported by such mechanism is substantially distributed over the supporting reach of the tread; and l To provide an endless track crawler mechanism with track supporting bogie rollers mounted on a pair of bogie yokes that are pivotally connected to the chassis of the crawler mechanism in such fashion that the yoke pair may be translated in-an upward or downward direction to compensate for large irregularities of the ground.

The following portion of this specification in conjunction with the attached drawings provides a written description of the present invention and of the manner of using it in such clear, full, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected to make and use the same. ln addition, preferred embodiments of the invention are disclosed in detail in order to set forth the best modes contemplated by the inventor for carrying out the invention. However, the specific embodiment of the invention disclosed here does not represent, in any fashion, the full scope of the invention.

Onthe contrary, the invention may be employed in many different embodiments. Therefore, the conclusion of the descriptive portion of this specification, the subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in numbered claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of a first embodiment of the endless track crawler mechanism comprising the invention, v

FIG. 2 is a plan view of the crawler mechanism shown in FIG'. l,

FIG. 3.is a cross section view taken along the line 3-3 of FIG. l,

FIG. 4 is a cross section view taken along the line 4-4 of FIG. l,

FIG. 5 is a perspective view of a second embodiment of the endless track crawler mechanism comprising the present invention, and

FIG. 6 is a perspective view of various components that vcomprise the first embodiment of the present invention.v

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, FIGS. 1 and 2 illustrate respectively a side and top view of a first embodiment of an endless track crawler mechanism that comprises the present invention and is particularly suited to serve as a supporting truck for large stripping shovels such as those shown in U.S. Pats. No. 3,258,143 and No. 3,376,983. When utilized with large stripping shovels, the shovel base frame (not shown) is mounted on four such crawler mechanisms located at the corners of the frame. The loads from the base are transmitted to the crawler mechanisms through hydraulic jacks (not shown) having ball shaped lower ends. 5,

The first embodiment is comprised of a composite welded and cast steel chassis 1 in the top side of which is a socket seat 2 which securely holds the ball shaped end of one ofthe hydraulic jacks. Each crawler mechanism is independently driven by a motor (not shown) that mounts on the chassis l. The drive gears (not shown) are totally enclosed in a compartment 3 at one end of the chassis 1 and at the chassis opposite end is a connecting means 4 for fastening steering members (not shown) to the mechanism. On each side of the chassis 1 is a track S of wide face, long pitch, cast links 6 of alloy, heat treated steel, connected by'large diameter special steel pins (not shown). To maintain tension on the tracks 5, take-up tumblers 7 of large diameter are mounted on a take-up axle 8 which slides in guides (not shown) cast integral with the chassis l. The tracks are driven by large diameter cast alloy steel tumblers 9 having outside lugs 10 to engage the tracks 5. The drive tumblers 9 are affixed on a drive shaft l1 which turns in bearings (not shown) in the truck chassis l. Mounted on the chassis 1 between the take-up tumblers 7 and the drive tumblers 9 are a pair of spaced apart bogie assemblies 13 and 14 which consist of similar type pairs of bogie yokes 15 and four bogie rollers 16, but have respectively bogie shafts 17 and 18 which differ from one another as will be described below. Illustrated by the cross section view of FIG. 3, the shaft 17 is held securely by sidewalls 19 and 20 of the crawler chassis l to prevent it from moving in either a vertical or horizontal direction. In contrast, as shown in FIG. 4, the shaft 18 fits through vertical notches 21 in the sidewalls 19 and 20 of the chassis l and there is enough clearance between the shaft 18 and the sidewalls 19 and 20 to permit the shaft 18 to pivot a limited distance in a vertical direction.

In FIG. 6 the tracks 5 and all but fragments of the chassis sidewall 20 have been left out to show more clearly, from left to right, the drive tumblers 9, mounted on the drive shaft 11, the pivotal bogie assembly 14, the fixed bogie assembly 13 and the take-up tumblers 7 mounted on the take-up axles 8. The fragments of the chasis sidewall 20 are shown at one end of each bogie assembly 13 and 14 to depict the disposition of the bogie shafts 17 and 18 through the sidewall 20. Part of one of the sidewall notches 2l through which the shaft 18 protrudes can clearly be seen while the sidewall 20 closely surrounds the shaft 17. To support the chassis l while capable of pivoting vertically to conform to the supporting terrain, the shaft 18 has an integral upper convex portion 22 medially positioned between its ends. Shown in FIG. 4, atop the convex portion 22 of the shaft 18 is a concave saddle 24 interfitting with a support plate 25 which is an integral part of the chassis 1. The support plate 25 and the saddle 24 are secured together as by bolts 26. The saddle 24 rests on the shaft convex portion 22 but is not connected to the shaft 18, hence, the shaft 18 is free to pivot about the saddle. However, this pivotal movement of the shaft 18 is limited by the size of the notches 21 in the chassis sidewalls 19 and 20.

As illustrated in FIG. 6, pivotally mounted on opposite ends of the shafts 17 and 18 are the bogie yokes 15 which serve as chassis supporting means. Each bogie yoke 15 has a center spacing block 27 affixed between two bogie roller axle brackets 28. A mounting bore 29 is formed through the two axle brackets 28 as well as the spacing block 27. The ends of the shafts 17 and 18 are journaled through the bores 29 to support the bogie yokes 15 securely held on the shaft ends by O-clamps 3l. A pair of roller axles 32 are mounted between the ends of the axle brackets 28 and a pair of the bogie rollers 16 are rotatably disposed on the axles 32.

In FIG. 5 a second embodiment of the crawler mechanism is illustrated which includes a chassis 33 in the center of which is a socket seat 34 for securing the ball end of one of the shovel hydraulic jacks (not shown). On each end of the chassis 33 is a pin type connecting means 34 for fastening the mechanism to a steering means (not shown). The crawler mechanism employs a pair of tracks 35 on both sides of the chassis 33. Mounting the tracks 35 are a take-up tumbler 36 mounted onv a shaft 37, a drive tumbler 38 mounted on a drive shaft 39 and a roller member 40 mounted on a coupling shaft 41; each of the shafts 37, 39 and 4l are positioned through a track frame 42, thus, forming pivotal tumbler assemblies 43 and 44, which may be seen, and 45 and 46 that are on the opposite sides of the chassis 33 and may only partially be seen. The four tumbler assemblies 43-46 substitute for the pivotal bogie yokes of the first embodiment and each such assembly is independently powered by its own motor 47 mounted atop thechassis 33. The tumbler assemblies 43-46 are pivotally connected in pairs to the chassis 33, a front pair 44 and 46 and a rear pin 43 and 45, by the coupling shafts 41 that also mount the roller members 40. The shaft 41 that is associated with the front pair of tumbler assemblies 44 and 46 has a limited freedom of vertical movement with respect to the chassis 33 and similar to that of the pivotal bogie shaft of the first embodiment to permit vertical translation of its connected tumbler assemblies. The shaft 41 associated with the rear pair of tumbler assemblies 43 and 45 is fixed with respect to the chassis 33. Thus, this embodiment although structurally dissimilar to the first embodiment, operatively duplicates that embodiment.

Through the utilization of the bogie yokes l5 or the pivotal tumbler assemblies 43-46, when the crawler mechanism of the present invention is traversing over terrain with only small irregularities the pivotal motion of the yokes l5 or the assemblies 43-46 about the ends of their respective shafts allows the crawler mechanism to maintain multiple points of contact with the terrain and serves to distributively support the vehicle. However, in instances when the crawler mechanism is traversing terrain with large irregularities, such pivotal movement of the bogie yokes l5 or the assemblies 43-46 may not be sufficient to maintain the necessary points of contact with the terrain. lt is in these instances that the pivotal movement of the shafts 18 or 41 about the chassis saddle is of principle importance to provide for limited vertical translation of the bogie yokes l5 or the assemblies 43-46 respectively disposed on their ends. This vertical translation ensures that each dual crawler will lalways-have at least eight points of contact with the ground on which it-is supported. Hence, in maximum stress situations the stresses will be distributed over at least'eight points.v

Thus, the embodiments of the invention shown and described herein provide an improved crawler mechanism for large strip mining shovels or the like to provide multiple points of contact between the terrain the shovels traverse and the crawler mechanisms. Also, the present invention provides a structure such that the previously conventional crawler mechanisms can be converted with relative ease to embody the structure and provide the advantages of the present invention.

Although preferred embodiments of the invention v have been shown, it will be obvious that various modifivcations are possible without departure from the spirit of the invention. The invention is of course not limited in use with excavator shovels but may be advantageously utilized with various types of vehicles having crawler mechanisms that support unusually heavy structures.

I claim:

1. An endless track crawler mechanism, a plurality of which are used to support and drive an excavator comprisingthe combination of:

a chassis; supporting propel drive and connecting means for connection to a steering means;

a plurality of substantially parallel horizontally spaced shafts mounted transversely of said chassis to support said chassis, at leastl one of said shafts being mounted for pivotal movement independently of the other of said shafts in a generally vertical plane; i

chassis supporting means pivotally mounted on each end of atleast some of said plurality of shafts, each of said chassis supporting means mounting a plurality of rotatable members on opposite sides of said shafts; and

a plurality of endless tracks with at least one of said endless tracks on each side of ,said chassis, and being mounted with portions lying between one of said chassis supporting means and a supporting terram. i

.2. An endless track crawler mechanismas set forth in claim 1 wherein:

only one of said shafts ispivotally mounted; said chassis has an integrally formedsupport plate;

` 4saicl pivotally mounted-shaft has an upper convex portion medially positioned between its ends; and

said support plate has a concave saddle bearing surface slidably seated on said upper convex portion of the pivotally mounted shaft.

3. An endless track crawler mechanism comprising the combination of:

a chassis, supporting propel drive and said chassis being adapted to be steered by an external force;

a plurality of substantially parallel horizontally spaced bogie shafts mounted to support said chassis, at least one of said bogie shafts being pivotally mounted;

a bogie yoke pivotally mounted on each end of each of said plurality of bogie shafts and mounting a pair of rotatable bogie rollers on opposite sides of said bogie shaft;

and a plurality of endless tracks, each of said endless tracks being mounted to surround at least one of said bogie yokes with a portion of its length lying between said bogie rollers and a supporting terrain.

4l. An endless track crawler mechanism as set forth in claim 3 wherein:

one of said bogie shafts is pivotally mounted;

said chassis has an integrally formed support plate;

said pivotally mounted bogie shaft has an upper convex portion medially positioned between its ends; and

a concave saddle interfits with said support plate and rests on said upper convex portion of the pivotally mounted bogie shaft.

'5. An endless track crawler mechanism comprising the combination of:

a chassis having an integrally formed support plate secured to a concave saddle, supporting propel drive and said chassis being adapted to be steered by an external steering means;

a plurality of substantially parallel horizontally spaced coupling shafts mounted to support said chassis, at least one of said coupling shafts being pivotally mounted and having an upper convex portion medially positioned between its ends and mounted in said concave saddle;

a frame pivotally mounted on each end of each of porting terrain.

Il! It( lll l# ttf 

1. An endless track crawler mechanism, a plurality of which are used to support and drive an excavator comprising the combination of: a chassis, supporting propel drive and connecting means for connection to a steering means; a plurality of substantially parallel horizontally spaced shafts mounted Transversely of said chassis to support said chassis, at least one of said shafts being mounted for pivotal movement independently of the other of said shafts in a generally vertical plane; chassis supporting means pivotally mounted on each end of at least some of said plurality of shafts, each of said chassis supporting means mounting a plurality of rotatable members on opposite sides of said shafts; and a plurality of endless tracks with at least one of said endless tracks on each side of said chassis, and being mounted with portions lying between one of said chassis supporting means and a supporting terrain.
 2. An endless track crawler mechanism as set forth in claim 1 wherein: only one of said shafts is pivotally mounted; said chassis has an integrally formed support plate; said pivotally mounted shaft has an upper convex portion medially positioned between its ends; and said support plate has a concave saddle bearing surface slidably seated on said upper convex portion of the pivotally mounted shaft.
 3. An endless track crawler mechanism comprising the combination of: a chassis, supporting propel drive and said chassis being adapted to be steered by an external force; a plurality of substantially parallel horizontally spaced bogie shafts mounted to support said chassis, at least one of said bogie shafts being pivotally mounted; a bogie yoke pivotally mounted on each end of each of said plurality of bogie shafts and mounting a pair of rotatable bogie rollers on opposite sides of said bogie shaft; and a plurality of endless tracks, each of said endless tracks being mounted to surround at least one of said bogie yokes with a portion of its length lying between said bogie rollers and a supporting terrain.
 4. An endless track crawler mechanism as set forth in claim 3 wherein: one of said bogie shafts is pivotally mounted; said chassis has an integrally formed support plate; said pivotally mounted bogie shaft has an upper convex portion medially positioned between its ends; and a concave saddle interfits with said support plate and rests on said upper convex portion of the pivotally mounted bogie shaft.
 5. An endless track crawler mechanism comprising the combination of: a chassis having an integrally formed support plate secured to a concave saddle, supporting propel drive and said chassis being adapted to be steered by an external steering means; a plurality of substantially parallel horizontally spaced coupling shafts mounted to support said chassis, at least one of said coupling shafts being pivotally mounted and having an upper convex portion medially positioned between its ends and mounted in said concave saddle; a frame pivotally mounted on each end of each of said coupling shafts and mounting a drive tumbler, take-up tumbler and a roller member on opposite sides of said coupling shaft; and a plurality of endless tracks, one of said endless tracks being mounted to surround at least one of said frames with a portion of its length lying between said take-up and drive tumblers and a supporting terrain. 